Higher AFib ablation volumes linked with better outcomes



– The number of atrial fibrillation (Afib) catheter ablations a hospital did a year had a substantial, independent effect on patient outcomes in a study of more than 54,000 U.S. catheter ablations performed during 2010-2014.

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The results showed that the roughly one-third of studied hospitals with the lowest annual volume of catheter ablations performed, 20 or fewer, had twice the acute complication rate and twice the 30-day in-hospital mortality rate, compared with the hospitals that did 53 or more such procedures annually in patients with atrial fibrillation, Jim W. Cheung, MD, said while presenting a poster at the annual scientific sessions of the Heart Rhythm Society.

The data, taken from 1,738 U.S. hospitals during 2010-2014 and captured in the Nationwide Readmissions Database, also showed that 79% of these hospitals performed 20 or fewer catheter ablations for atrial fibrillation (AFib) annually, with 63% doing 10 or fewer cases per year during the 5 years studied.

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Dr. Jim W. Cheung

The findings raise the question of whether U.S. guidelines for catheter ablation of AFib should specify a minimum case volume for hospital programs, and if so, how high the minimum should be. Volume thresholds are “something to think about,” or a system to designate centers of excellence, Dr. Cheung suggested in a video interview. But interest in setting volume thresholds to better insure competence is often counterbalanced by concerns about patient access, he noted.

The prevailing U.S. guidelines for catheter ablation of AFib are in a 2017 statement from the Heart Rhythm Society and several collaborating groups (J Arrhythm. 2017 Oct;33[5]:369-409). The statement focused on operator volume rather than hospital volume and said that each operator should perform “several” AFib ablation procedures each month, which is generally understood to mean at least 2 per month or at least about 25 annually, commented Hugh Calkins, MD, chair of the panel that wrote the statement and professor of medicine at Johns Hopkins Medicine in Baltimore. The major rationale for setting a suggested minimum of about 25 cases/year came largely from a 2013 report that is cited as the first study to document a volume-outcome relationship for catheter ablation of AFib (Circulation. 2013 Nov 5;128[19]:2104-12), Dr. Calkins noted. “Volume does matter,” he agreed in an interview, but no society or organization monitors hospital or operator volumes, nor takes any steps when volumes are low.

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Dr. Hugh Calkins

The Nationwide Readmissions Database included 54,599 patients who underwent AFib catheter ablation during 2010-2014. Dr. Cheung and his associates divided these patients into rough tertiles based on the annual procedure volumes of the hospitals that performed these ablations. The 36% of patients treated at hospitals that did 20 or fewer procedures annually were on average older and had more comorbidities than the 31% treated at hospitals in the highest-volume tertile, which performed at least 53 ablations annually. In an analysis that adjusted for these demographic and clinical differences, patients ablated at the lower-volume hospitals had a statistically significant 2.06-fold higher rate of any complication and a 2.24-fold increased rate of in-hospital mortality, either during the index hospitalization or during a 30-day hospital readmission, reported Dr. Cheung, director of clinical electrophysiology research at Weill Cornell Medical College in New York. The increased rate of complications was driven by a fivefold increased rate of cardiac perforations, a greater than doubled periprocedural stroke rate, and a roughly 50% increased rate of vascular complications, compared with the highest-volume hospitals and after adjustment for baseline differences.

Dr. Cheung has been a consultant to Abbott and Biotronik, and has received fellowship support from Biosense Webster, Biotronik, Boston Scientific, Medtronic, and St. Jude. Dr. Calkins disclosed ties to Abbott, Altathera, AtriCure, Boehringer Ingelheim, Boston Scientific, Medtronic, St. Jude, and MRI Interventions.

SOURCE: Cheung JW. HRS 2019, Abstract S-P001-123.

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